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Fencer Vulns
medium 6.5

CVE-2026-27585 json

Caddy's improper sanitization of glob characters in file matcher may lead to bypassing security protections

published 2026-02-24 8 mo ago modified 2026-06-17 4 mo ago also GHSA-4xrr-hq4w-6vf4 , GO-2026-4535 , EUVD-2026-8539

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, the path sanitization routine in file matcher doesn't sanitize backslashes which can lead to bypassing path related security protections. It affects users with specific Caddy and environment configurations. Version 2.11.1 fixes the issue.

Patch / fix

  • go github.com/caddyserver/caddy/v2 2.11.1
  • caddyserver caddy 2.11.1
  • caddy Debian 12 2.6.2-5+deb12u1
  • caddy Debian 13 2.6.2-12+deb13u1
  • caddy Debian 14 2.11.2-1

debian advisories DEBIAN-CVE-2026-27585

  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260226T182644-150000.1.149.1

suse advisories SUSE-SU-2026:0757-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

  • caddy Alpine 3.23 2.11.2-r0
  • caddy Alpine 3.24 2.11.1-r0

alpine advisories ALPINE-CVE-2026-27585

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-27585 updated cvss 6.5

github.com/caddyserver/caddy/v2/modules/caddyhttp/fileserver: Caddy: Path security bypass due to unsanitized backslashes

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/caddyserver/caddy/security/advisories/GHSA-4xrr-hq4w-6vf4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
go github.com/caddyserver/caddy/v2
<2.11.1
2.11.1

Affected products

  • caddyserver caddy

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.